PubMed Health⌕ Search

Biomedical subjects

M Trucco

Publications and source records attributed to M Trucco.

At least 55 records · Page 3Linked to original sources
PubMed1999

Naturally processed and presented epitopes of the islet cell autoantigen IA-2 eluted from HLA-DR4.

During immune responses, antigen-presenting cells (APCs) process antigens and present peptide epitopes complexed with human leukocyte antigen (HLA) molecules. CD4 cells recognize these naturally processed and presented epitopes (NPPEs) bound to HLA class II molecules. Epitope identification is important for developing diagnostic and therapeutic tools for immune-mediated diseases and providing insight into their etiology, but current approaches overlook effects of natural processing on epitope selection. We have developed a technique to identify NPPEs using mass spectrometry (MS) after antigen is targeted onto APCs using a lectin-based antigen delivery system (ADS). We applied the technique to identify NPPEs of the intracellular domain of the type 1 diabetes mellitus-associated (type 1 DM-associated) autoantigen insulinoma-associated-2 (IA-2ic), presented by HLA-DR4 (0401). IA-2ic-derived NPPEs eluted from HLA-DR4 constitute 6 sets of peptides nested around distinct core regions. Synthetic peptides based on these regions bind HLA-DR4 and elicit primary T-cell proliferation frequently in HLA-DR4-positive type 1 DM patients, but rarely in non-HLA-DR4 patients, and in none of the HLA-DR4 nondiabetic controls we tested. This flexible, direct approach identifies an HLA allele-specific map of NPPEs for any antigen, presented by any HLA class II molecule. This method should enable a greater understanding of epitope selection and lead to the generation of sensitive and specific reagents for detecting autoreactive T cells.

Adolescent↗
PubMed1999

Sequence analysis of the diabetes-protective human leukocyte antigen-DQB1*0602 allele in unaffected, islet cell antibody-positive first degree relatives and in rare patients with type 1 diabetes.

The human leukocyte antigen (HLA)-DQA1*0102/DQB1*0602/DRB1*1501 (DR2) haplotype confers strong protection from type 1 diabetes. Growing evidence suggests that such protection may be mostly encoded by the DQB1*0602 allele, and we reported that even first degree relatives with islet cell antibodies (ICA) have an extremely low diabetes risk if they carry DQB1*0602. Recently, novel variants of the DQB1*0602 and *0603 alleles were reported in four patients with type 1 diabetes originally typed as DQB1*0602 with conventional techniques. One inference from this observation is that DQB1*0602 may confer absolute protection and may never occur in type 1 diabetes. By this hypothesis, all patients typed as DQB1*0602 positive with conventional techniques should carry one of the above diabetes-permissive variants instead of the protective DQB1*0602. Such variants could also occur in ICA/DQB1*0602-positive relatives, with the implication that their diabetes risk could be significantly higher than previously estimated. We therefore sequenced the DQB1*0602 and DQA1*0102 alleles in all ICA/DQB1*0602-positive relatives (n = 8) previously described and in six rare patients with type 1 diabetes and DQB1*0602. We found that all relatives and patients carry the known DQB1*0602 and DQA1*0102 sequences, and none of them has the mtDNA A3243G mutation associated with late-onset diabetes in ICA-positive individuals. These findings suggest that diabetes-permissive DQB1*0602/3 variants may be very rare. Thus, although the protective effect associated with DQB1*0602 is extremely powerful, it is not absolute. Nonetheless, the development of diabetes in individuals with DQB1*0602 remains extremely unlikely, even in the presence of ICA, as confirmed by our further evaluation of ICA/DQB1*0602-positive relatives, none of whom has yet developed diabetes.

Adult↗
PubMed1999

Targeting autoimmune diabetes with gene therapy.

The autoimmune nature of insulin-dependent, or type 1, diabetes targets the beta-cells of the pancreas for destruction and results in a lifelong commitment to insulin replacement therapy. Although the number of formulations and dosing of insulin have become more sophisticated and more efficient in recent years, insulin therapy alone is unable to prevent nephropathy, retinopathy, or vascular and heart disease, which still occur in a large number of patients. Different approaches have been attempted to eliminate the requirement of exogenous insulin administration. Historically, these have included pancreatic and islet transplants, which were later combined with treatments intended to halt the destructive process directed against the islets. Despite significant advances made in all of these areas, each approach faces a hostile immunological response that frequently ends with the loss of the islets. Gene therapy-based approaches add a new dimension to the efforts aimed at specifically blocking the immunological attack against the islets in genetically at-risk individuals (autoimmunity) or the immunological response against transplanted allogeneic islets (rejection). This new technology may have an important role in the therapy and cure of type 1 diabetes.

Animals↗
PubMed1999

Adenoviral gene transfer of the interleukin-1 receptor antagonist protein to human islets prevents IL-1beta-induced beta-cell impairment and activation of islet cell apoptosis in vitro.

The beta-cells in the pancreatic islets of Langerhans are the targets of autoreactive T-cells and are destroyed in type 1 diabetes. Macrophage-derived interleukin-1beta (IL-1beta) is important in eliciting beta-cell dysfunction and initiating beta-cell damage in response to microenvironmental changes within islets. In particular, IL-1beta can impair glucose-stimulated insulin production in beta-cells in vitro and can sensitize them to Fas (CD95)/FasL-triggered apoptosis. In this report, we have examined the ability to block the detrimental effects of IL-1beta by genetically modifying islets by adenoviral gene transfer to express the IL-1 receptor antagonist protein. We demonstrate that adenoviral gene delivery of the cDNA encoding the interleukin-1 receptor antagonist protein (IL-1Ra) to cultured islets results in protection of human islets in vitro against IL-1beta-induced nitric oxide formation, impairment in glucose-stimulated insulin production, and Fas-triggered apoptosis activation. Our results further support the hypothesis that IL-1beta antagonism in in situ may prevent intra-islet proinsulitic inflammatory events and may allow for an in vivo gene therapy strategy to prevent insulitis and the consequent pathogenesis of diabetes.

Adenoviridae↗
PubMed1999

Involvement of Fas/FasL system in the pathogenesis of autoimmune diseases and Wilson's disease.

The interaction of Fas with FasL has been demonstrated to be implicated in the pathogenesis of several autoimmune and liver diseases. Recently, attention has been focused on the hypothesis that thyrocytes and beta cells undergo massive Fas/FasL-mediated apoptosis during autoimmune response. Similarly, hepatocyte cell death occurring following copper accumulation points towards the same mechanism.

Diabetes Mellitus, Type 1↗
PubMed1999

Genetics of Type 1 diabetes mellitus.

Type 1 diabetes or insulin-dependent diabetes mellitus (IDDM) is the archetypal example of a T cell-mediated autoimmune disease characterised by selective destruction of a single cell type: the insulin-producing beta-cells of the pancreatic islets of Langerhans. The pathogenic equation for IDDM presents a complex interrelation of genetic and environmental factors, most of which have yet to be identified. Based on the observed familial aggregation of IDDM, it is certain that there is a decided heritable genetic susceptibility for developing autoimmune diabetes. The well-known association of IDDM with certain human histocompatibility leukocyte antigen (HLA) alleles of the major histocompatibility complex (MHC) was a major step toward understanding the role of inheritance in IDDM. Landmark molecular biological investigations of diabetes HLA susceptibility genes provided great potential for insights into the molecular basis for the autoimmune nature of the disease, beginning a story that continues to unfold. Although the association of certain HLA alleles with IDDM is very strong, this genetic locus is estimated to account for less than 50% of genetic contributions to disease susceptibility. The search for non-HLA susceptibility genes has received great attention in recent years. Albeit genome wide searches are wrought with controversy, such studies have suggested the association of numerous non-MHC loci with Type 1 diabetes that will require careful follow-up investigation. Cell biological and genetic functional analyses will provide clues that are indispensable for further progress. The necessary studies include research on immunological abnormalities that are present many years before the clinical onset of Type 1 diabetes.

Alleles↗
PubMed1999

[Occupational stress in health care personnel].

BACKGROUND: Occupational stress results from the interaction of multiple risk factors, such as the physical environment, biological function disturbances, work content and organization and diverse psychosocial components. AIM: To study the frequency of symptoms and the main sources of job stress, perceived by professional and non professional health care workers and to compare gender differences. SUBJECTS AND METHODS: A group of specially designed, self-administered, questionnaires adapted by the main author and independently validated, were applied. The results of two symptoms, one work satisfaction, and one job stress scales are reported. RESULTS: One hundred sixteen women and 89 men were studied, 143 are professionals and 62 non professionals (clerical and nurse auxiliaries). Forty percent had symptoms of job stress and 82 subjects were defined as "probable cases", according to the ratings on the symptom scales. There were significant differences in the frequency of symptoms between professionals and non professionals (34.3 and 69.2% respectively). The main differences in symptoms, sources of job stress and dissatisfaction were more closely associated to the occupational level than to gender. CONCLUSIONS: A high frequency of job stress symptoms was observed in this sample of health care workers and the risk of occupational stress varies more with the occupational level than with gender.

Adult↗
PubMed1998

Idiopathic dilated cardiomyopathy: a superantigen-driven autoimmune disease.

BACKGROUND: Many cases of idiopathic dilated cardiomyopathy (IDC) result from an inflammatory myocarditis. The specific immunological mechanisms are not yet defined. Various autoimmune diseases are associated with superantigen-triggered immune responses, resulting in massive T-cell activation and tissue damage. We studied 3 cases in a search for evidence that such a phenomenon is also implicated in IDC. METHODS AND RESULTS: Myocardial, lymph node, and thymic tissue samples were obtained from IDC patients who were undergoing heart transplantation. Infiltrating immune-cell phenotypes and gene expression of T-cell receptor (TCR) alpha- and beta-chain variable (Valpha and Vbeta) regions were analyzed by immunostaining and polymerase chain reaction. Similar technical approaches were used to assay the tissues for the presence of coxsackievirus B (CVB). In all the specimens analyzed, an overexpression of the TCR Vbeta3, Vbeta7, and Vbeta13.1 gene families was detected among the infiltrating T cells. These tissues were also found to be CVB3-positive. In vitro exposure of peripheral blood mononuclear cells to lysates of cells infected with CVB3 was capable of stimulating expansion of the same TCR Vbeta families. The TCR Valpha repertoire was never found to be skewed. CONCLUSIONS: A superantigen-mediated immune response is involved in human heart disease. CVB3 may directly or indirectly trigger this response, suggesting a possible mechanistic link between CVB infection and myocarditis development progressing to IDC.

Animals↗
PubMed1998

Combined analysis of GAD65 and ICA512(IA-2) autoantibodies in organ and non-organ-specific autoimmune diseases confers high specificity for insulin-dependent diabetes mellitus.

There is evidence that insulin-dependent diabetes mellitus (IDDM) may develop in association with other non-beta-cell-specific autoimmune diseases. We aimed to assess whether autoantibodies to the islet cell antigens glutamic acid decarboxylase (Mr 65,000 isoform) (GAD65) and ICA512(IA-2), present alone or in combination, are limited to IDDM or also occur in other organ- or non-organ-specific autoimmune disorders. We determined the frequency of these autoantibodies by radioimmunoassay in 199 sera from patients with autoimmune thyroid diseases (AITD), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and primary biliary cirrhosis (PBC), and compared the results with those from 507 newly diagnosed patients with IDDM and 280 healthy controls. ICA512(IA-2) autoantibodies were detected exclusively in AITD with concurrent IDDM, but not in other autoimmune diseases without IDDM, whereas GAD65 autoantibodies exceeded the limit of normal in 67.7% (21 of 31) of patients with AITD who also had IDDM and in 5.5% (three of 55) of patients with PBC. The frequency of either GAD65 and/or ICA512(IA-2) autoantibodies was significantly higher in patients with AITD who also had IDDM (27 of 31, 87.1%) than in those with AITD alone (one of 53, 1.9%; P<10(-6)), but was not significantly different from those patients with newly diagnosed IDDM (418 of 507, 82.4%). Neither patients with organ- or non-organ-specific autoimmune diseases without IDDM nor healthy controls had autoantibodies against both GAD65 and ICA512(IA-2). Despite the fact that one of the two autoantibodies was occasionally detected in patients with non-beta-cell-specific autoimmune diseases without IDDM, combined determination of GAD65 and ICA512(IA-2) autoantibodies specifically identified IDDM in the majority of patients with AITD. In conclusion, because of the strong association of IDDM with AITD, testing for multiple islet autoanti-bodies could be useful as a predictive marker for risk of progression to IDDM onset amongst patients with autoimmune thyroid disorders.

Adolescent↗
PubMed1998

Hashimoto's thyroiditis and insulin-dependent diabetes mellitus: differences among individuals with and without abnormal thyroid function.

Insulin-dependent diabetes mellitus probands from the Familial Autoimmune and Diabetes Study were evaluated for autoimmune thyroid disease (n = 265). The prevalence of Hashimoto's thyroiditis was 26.6%; 42.0% of these individuals were euthyroid, and 58.0% were hypothyroid. There was a female predominance among hypothyroid and euthyroid Hashimoto's cases compared to those with no thyroid disease (75% vs. 72.4% vs. 41.6%; P < 0.001). Insulin-dependent diabetes mellitus patients with hypothyroid Hashimoto's thyroiditis were more likely to report another autoimmune disease compared to euthyroid Hashimoto's patients or individuals with no thyroid disease (30.8% vs. 17.2% vs. 13.9%; P < 0.01). Sex-specific analysis revealed that this difference was significant for men but not for women. Both euthyroid and hypothyroid Hashimoto's cases were more likely to have a family history of the disease (66.7% vs. 69.2% vs. 47.7%; P < 0.05). No differences were observed in the prevalence of DQA1*0501-DQB1*0201 or DQA1*0301-DQB1*0302 across the three groups. Body mass index, lipid levels, glycemic control, and diabetes complications were also similar. However, euthyroid Hashimoto's women were more likely to report spontaneous abortions than those with hypothyroid Hashimoto's thyroiditis or no thyroid disease (23.8% vs. 61.5% vs. 29.1%; P < 0.05). These data suggest that gender-specific risk factors may be primary determinants of Hashimoto's thyroiditis and other autoimmune diseases among women. However, disease-specific determinants may also increase susceptibility to other autoimmune diseases.

Abortion, Spontaneous↗
PubMed1998

Islet cell autoimmunity in white and black children and adolescents with IDDM.

OBJECTIVE: To compare the frequency of islet cell antibodies (ICA) and antibodies to GAD65 and IA-2(ICA512) between black and white children and adolescents at the diagnosis of IDDM in a large consecutive series of cases from Children's Hospital of Pittsburgh. RESEARCH DESIGN AND METHODS: ICA and antibodies to GAD65 and IA-2 were measured in 437 white and black children and adolescents who were diagnosed with IDDM at < 19 years of age at Children's Hospital of Pittsburgh from January 1983 to December 1985, from January to December 1989, and from January 1996 to December 1997. RESULTS: The prevalence of ICA(H), GAD65, and IA-2 antibodies was significantly lower in blacks than whites at onset of the disease. In contrast, the prevalence of ICA(R) alone was higher in blacks. None of the antibodies were present in 12% of the blacks compared with 4% in whites. The same pattern was seen in both sexes. The prevalence of antibodies in white patients with onset of IDDM at <11 years of age was no different than in those who developed IDDM during adolescence. In contrast, black patients showed a significantly lower prevalence of almost all antibodies in the adolescent group. CONCLUSIONS: Black adolescents were more likely to not have antibodies, suggesting either that they have a nonautoimmune type of diabetes or that antibodies are not being detected by these assays.

Adolescent↗
PubMed1998

[Recent alcohol and drug consumption in victims of work related accidents].

BACKGROUND: Twenty to twenty two percent of work related accidents have a direct or indirect relationship with recent alcohol use. AIM: To detect recent alcohol or drug use in patients who required hospitalization for severe work related accidents. PATIENTS AND METHODS: Blood and urine samples were obtained from patients admitted to a hospital within 6 hours of an accident severe enough to require hospitalization. Blood alcohol and urinary metabolites of cocaine, marijuana, amphetamines and benzodiazepines were measured. Patient identity was kept confidential throughout the study. Once patients were stabilized, they were interviewed by a psychologist that was blind to laboratory results. RESULTS: Two hundred thirty men and 18 women were studied and 29% (30% of men and 17% of women) had recent use of alcohol or drugs. The most common substances were alcohol in 15% and benzodiazepines in 13%. Use of alcohol or drugs was found in 21% of professionals, in 33% of other occupational levels, half of agricultural workers and 25% of commerce workers. Only two of 60 positive cases, admitted substance use during the interview. Most of negative cases admitted the use of alcohol or other drugs during the month prior to the accident. CONCLUSIONS: Recent use of alcohol and drugs is frequent among severe work related accident victims. Probably, a high proportion of these subjects are problem drinkers. The combination of alcohol and benzodiazepines is an additional risk factor.

Accidents, Occupational↗
PubMed1998

Immunoglobulin A supplementation abrogates bacterial translocation and preserves the architecture of the intestinal epithelium.

BACKGROUND: Breast milk has been shown to prevent gut-origin infections in neonates through undefined mechanisms. Putative protective factors in breast milk include immunoglobulin (Ig)A, IgG, and lactoferrin. We examined their role in bacterial translocation in neonatal rabbits. METHODS: IgA, IgG, and lactoferrin were isolated from rabbit breast milk through gel filtration and ion-exchange chromatography. Neonates were randomized to receive breast milk, formula alone, or formula supplemented with IgA, IgG, or lactoferrin. Quantitative cultures were performed on day 7 for bacterial translocation. Hematoxylin-eosin-stained sections of distal ileum were examined by light microscopy. Transmucosal bacterial passage was determined in vitro, and the ileal mucosal membranes were examined by confocal microscopy. RESULTS: IgA supplementation abrogated bacterial translocation. IgG and lactoferrin had no significant effect. Neonates that received IgA or breast milk gained more weight than those in the other groups. IgA reduced transmucosal bacterial passage in vitro. In contrast to the normal-appearing distal ileum of neonates fed breast milk, intestinal epithelium from neonates that received formula or formula with IgG or IgA demonstrated prominent vacuoles by light microscopy. Those fed formula alone or formula with lactoferrin had slightly shortened villi. CONCLUSIONS: IgA supplementation prevents bacterial translocation by enhancing gut mucosal barrier function.

Animals↗
PubMed1997

Analysis of the alpha/beta T-cell receptor repertoire by competitive and quantitative family-specific PCR with exogenous standards and high resolution fluorescence based CDR3 size imaging.

The characterization of the human T-cell receptor (TCR) repertoire in various physiological and pathological conditions has become an important tool in studies of the immune response. Therefore, a number of PCR based strategies for the semiquantitative analysis of the TCR repertoire have been described. Family specific amplification of TCR cDNA has been employed in a number of studies often with contradictory results. We have developed a strategy utilizing exogenous standards with homologous primer binding sites for the quantitative analysis of the alpha/beta T-cell receptor repertoire. This system allows the detection of even minute differences in T-cell populations based on quantitative PCR (Q-PCR) and competitive PCR (C-PCR). Results presented here demonstrate that expansions of T-cell subsets as defined by the specificity of the variable gene segments can be readily monitored when exceeding 1% of the total repertoire. In addition, the proposed method reveals direct information of CDR3 size heterogeneity and can be used to estimate the T-cell repertoire complexity and monitor clonal expansions. We discuss variables such as cell number and experimental conditions influencing accuracy and reproducibility of the analyses. We have used this protocol based on non-radioactive techniques for characterization of the fine specificity of the T-cell repertoire in peripheral and organ-infiltrating T-lymphocytes. The analyses revealed information about polyclonal or clonal expansion of T-cells in vivo and in vitro following various stimuli such as superantigenic stimulation of T-cell subsets as well as antigen-driven shaping of the alpha/beta T-cell repertoire in autoimmune and infectious diseases.

DNA Primers↗
PubMed1997

Evidence for engraftment of human bone marrow cells in non-lethally irradiated baboons.

BACKGROUND: Prior to organ harvesting, an attempt was made to modulate the donor's immune responses against prospective xenogeneic recipients by infusion of "recipient-type" bone marrow. METHODS: For this purpose, baboons conditioned with total lymphoid irradiation were given 6 x 10(8) unmodified human bone marrow cells/kg body weight with no subsequent treatment. RESULTS: Animals survived until they were euthanized at 18 months. Using primers specific for human chorionic gonadotrophin gene, the presence of human DNA was confirmed by polymerase chain reaction in the blood of one animal for up to 18 months after cell transplantation; in the other animal, xenogeneic chimerism became undetectable in the blood at 6 months after bone marrow infusion. However, tissue samples obtained from both animals at the time they were euthanized had evidence of donor (human) DNA. Additionally, the presence of donor DNA in individually harvested colonies of erythroid and myeloid lineages suggested that infused human bone marrow cells had engrafted across the xenogeneic barrier in both baboons. CONCLUSIONS: Bone marrow transplantation from human to baboon leads to establishment of chimerism and modulation of donor-specific immune reactivity, which suggests that this strategy could be reproducibly employed to create "surrogate" tolerogenesis in prospective donors for subsequent organ transplantation across xenogeneic barriers.

Animals↗
PubMed1997

HLA-DP2: self peptide sequences and binding properties.

Although self peptides bound to HLA-DQ and, especially, HLA-DR allotypes have been described in some detail, few ligands that bind to HLA-DP have been identified. Toward this aim, naturally processed peptides were isolated from immunoaffinity-purified HLA-DP2 molecules expressed in cultured B lymphocytes. The size distribution of the peptide repertoire is generally similar to those reported for self peptides bound to HLA-DR and HLA-DQ molecules. Twelve peptides representing individual sequences including two nested sets were sequenced by mass spectrometry and/or N-terminal Edman analysis. Source proteins included MHC molecules and other integral membrane proteins as well as secretory and serum proteins. No dominant amino acid markers suggestive of particular enzymatic processing events were detected. Peptide specificity and affinity were examined in binding assays using synthetic peptides and purified HLA-DP and HLA-DR molecules. Anchor residues were tentatively assigned using alanine-substituted analogues of two self peptides. Some structural features of HLA-DP2 that may relate to peptide binding are considered.

Amino Acid Sequence↗
PubMed1997

Nitric oxide primes pancreatic beta cells for Fas-mediated destruction in insulin-dependent diabetes mellitus.

Fas is an apoptosis-inducing surface receptor involved in controlling tissue homeostasis and function at multiple sites. Here we show that beta cells from the pancreata of newly diagnosed insulin-dependent diabetes mellitus (IDDM) patients express Fas and show extensive apoptosis among those cells located in proximity to Fas ligand-expressing T lymphocytes infiltrating the IDDM islets. Normal human pancreatic beta cells that do not constitutively express Fas, become strongly Fas positive after interleuken (IL)-1beta exposure, and are then susceptible to Fas-mediated apoptosis. NG-monomethyl-L-arginine, an inhibitor of nitric oxide (NO) synthase, prevents IL-1beta-induced Fas expression, whereas the NO donors sodium nitroprusside and nitric oxide releasing compound (NOC)-18, induce functional Fas expression in normal pancreatic beta cells. These findings suggest that NO-mediated upregulation of Fas contributes to pancreatic beta cell damage in IDDM.

Adult↗